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| author | Christopher Speller <crspeller@gmail.com> | 2016-05-12 15:08:58 -0400 |
|---|---|---|
| committer | Christopher Speller <crspeller@gmail.com> | 2016-05-12 16:37:29 -0400 |
| commit | 84d2482ddbff9564c9ad75b2d30af66e3ddfd44d (patch) | |
| tree | 8bfa567d2b6381f4a996ada2deff8a16aa85a3ac /vendor/github.com/disintegration/imaging/README.md | |
| parent | d1efb66ad7b017f0fbfe6f0c20843b30f396e504 (diff) | |
| download | chat-84d2482ddbff9564c9ad75b2d30af66e3ddfd44d.tar.gz chat-84d2482ddbff9564c9ad75b2d30af66e3ddfd44d.tar.bz2 chat-84d2482ddbff9564c9ad75b2d30af66e3ddfd44d.zip | |
Updating go depencancies. Switching to go1.6 vendoring (#2949)
Diffstat (limited to 'vendor/github.com/disintegration/imaging/README.md')
| -rw-r--r-- | vendor/github.com/disintegration/imaging/README.md | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/vendor/github.com/disintegration/imaging/README.md b/vendor/github.com/disintegration/imaging/README.md new file mode 100644 index 000000000..3dcea2000 --- /dev/null +++ b/vendor/github.com/disintegration/imaging/README.md @@ -0,0 +1,198 @@ +# Imaging
+
+[](https://godoc.org/github.com/disintegration/imaging)
+[](https://travis-ci.org/disintegration/imaging)
+[](https://coveralls.io/github/disintegration/imaging?branch=master)
+
+Package imaging provides basic image manipulation functions (resize, rotate, flip, crop, etc.).
+This package is based on the standard Go image package and works best along with it.
+
+Image manipulation functions provided by the package take any image type
+that implements `image.Image` interface as an input, and return a new image of
+`*image.NRGBA` type (32bit RGBA colors, not premultiplied by alpha).
+
+## Installation
+
+Imaging requires Go version 1.2 or greater.
+
+ go get -u github.com/disintegration/imaging
+
+## Documentation
+
+http://godoc.org/github.com/disintegration/imaging
+
+## Usage examples
+
+A few usage examples can be found below. See the documentation for the full list of supported functions.
+
+### Image resizing
+```go
+// resize srcImage to size = 128x128px using the Lanczos filter
+dstImage128 := imaging.Resize(srcImage, 128, 128, imaging.Lanczos)
+
+// resize srcImage to width = 800px preserving the aspect ratio
+dstImage800 := imaging.Resize(srcImage, 800, 0, imaging.Lanczos)
+
+// scale down srcImage to fit the 800x600px bounding box
+dstImageFit := imaging.Fit(srcImage, 800, 600, imaging.Lanczos)
+
+// resize and crop the srcImage to fill the 100x100px area
+dstImageFill := imaging.Fill(srcImage, 100, 100, imaging.Center, imaging.Lanczos)
+```
+
+Imaging supports image resizing using various resampling filters. The most notable ones:
+- `NearestNeighbor` - Fastest resampling filter, no antialiasing.
+- `Box` - Simple and fast averaging filter appropriate for downscaling. When upscaling it's similar to NearestNeighbor.
+- `Linear` - Bilinear filter, smooth and reasonably fast.
+- `MitchellNetravali` - А smooth bicubic filter.
+- `CatmullRom` - A sharp bicubic filter.
+- `Gaussian` - Blurring filter that uses gaussian function, useful for noise removal.
+- `Lanczos` - High-quality resampling filter for photographic images yielding sharp results, but it's slower than cubic filters.
+
+The full list of supported filters: NearestNeighbor, Box, Linear, Hermite, MitchellNetravali, CatmullRom, BSpline, Gaussian, Lanczos, Hann, Hamming, Blackman, Bartlett, Welch, Cosine. Custom filters can be created using ResampleFilter struct.
+
+**Resampling filters comparison**
+
+Original image. Will be resized from 512x512px to 128x128px.
+
+
+
+Filter | Resize result
+---|---
+`imaging.NearestNeighbor` | 
+`imaging.Box` | 
+`imaging.Linear` | 
+`imaging.MitchellNetravali` | 
+`imaging.CatmullRom` | 
+`imaging.Gaussian` | 
+`imaging.Lanczos` | 
+
+**Resize functions comparison**
+
+Original image:
+
+
+
+Resize the image to width=100px and height=100px:
+
+```go
+dstImage := imaging.Resize(srcImage, 100, 100, imaging.Lanczos)
+```
+
+
+Resize the image to width=100px preserving the aspect ratio:
+
+```go
+dstImage := imaging.Resize(srcImage, 100, 0, imaging.Lanczos)
+```
+
+
+Resize the image to fit the 100x100px boundng box preserving the aspect ratio:
+
+```go
+dstImage := imaging.Fit(srcImage, 100, 100, imaging.Lanczos)
+```
+
+
+Resize and crop the image with a center anchor point to fill the 100x100px area:
+
+```go
+dstImage := imaging.Fill(srcImage, 100, 100, imaging.Center, imaging.Lanczos)
+```
+
+
+### Gaussian Blur
+```go
+dstImage := imaging.Blur(srcImage, 0.5)
+```
+
+Sigma parameter allows to control the strength of the blurring effect.
+
+Original image | Sigma = 0.5 | Sigma = 1.5
+---|---|---
+ |  | 
+
+### Sharpening
+```go
+dstImage := imaging.Sharpen(srcImage, 0.5)
+```
+
+Uses gaussian function internally. Sigma parameter allows to control the strength of the sharpening effect.
+
+Original image | Sigma = 0.5 | Sigma = 1.5
+---|---|---
+ |  | 
+
+### Gamma correction
+```go
+dstImage := imaging.AdjustGamma(srcImage, 0.75)
+```
+
+Original image | Gamma = 0.75 | Gamma = 1.25
+---|---|---
+ |  | 
+
+### Contrast adjustment
+```go
+dstImage := imaging.AdjustContrast(srcImage, 20)
+```
+
+Original image | Contrast = 20 | Contrast = -20
+---|---|---
+ |  | 
+
+### Brightness adjustment
+```go
+dstImage := imaging.AdjustBrightness(srcImage, 20)
+```
+
+Original image | Brightness = 20 | Brightness = -20
+---|---|---
+ |  | 
+
+
+### Complete code example
+Here is the code example that loads several images, makes thumbnails of them
+and combines them together side-by-side.
+
+```go
+package main
+
+import (
+ "image"
+ "image/color"
+
+ "github.com/disintegration/imaging"
+)
+
+func main() {
+
+ // input files
+ files := []string{"01.jpg", "02.jpg", "03.jpg"}
+
+ // load images and make 100x100 thumbnails of them
+ var thumbnails []image.Image
+ for _, file := range files {
+ img, err := imaging.Open(file)
+ if err != nil {
+ panic(err)
+ }
+ thumb := imaging.Thumbnail(img, 100, 100, imaging.CatmullRom)
+ thumbnails = append(thumbnails, thumb)
+ }
+
+ // create a new blank image
+ dst := imaging.New(100*len(thumbnails), 100, color.NRGBA{0, 0, 0, 0})
+
+ // paste thumbnails into the new image side by side
+ for i, thumb := range thumbnails {
+ dst = imaging.Paste(dst, thumb, image.Pt(i*100, 0))
+ }
+
+ // save the combined image to file
+ err := imaging.Save(dst, "dst.jpg")
+ if err != nil {
+ panic(err)
+ }
+}
+```
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